Reactive Power Compensation using Vehicle-to-Grid enabled Bidirectional Off-Board EV Battery Charger

This paper investigates the application of a grid-connected off-board Electric vehicle (EV) battery charger on the reactive power compensation and simultaneously use as a battery charger (grid-to-vehicle (G2V)) and power generator (vehicle-to-grid (V2G)). The topology of the charger consists of a grid facing front-end AC-DC cascaded H-bridge bidirectional converter, which controls the power flow between the grid and EV battery using a back-end DC-DC bidirectional converter. The charger configuration provides galvanic isolation at the user end from the rest of the system as a safety measure. The proposed control algorithm follows the active power command for G2V and V2G operation along with reactive power command from the utility grid when requested, by controlling EV current and battery current. Furthermore, an adaptive notch filter based controller is designed for system phase estimation and generated reference current synchronization. The proposed control algorithm eliminates phase locked loop (PLL) from the controller design. As a result, the computational complexity of the controller reduces with improved steady-state and trainset performance. Furthermore, a 12.6 kVA off-board charger simulation model is developed in MATLAB/Simulink environment and the performance of the proposed control algorithm is tested during G2V, V2G, and reactive power compensation operation of the EV charger.